CTD after 3.7.4 update related to AI (MSFS2020)

[DownedAviator]

I have just returned home and do not have time to deal with this at the moment, but I have a question for anyone who has tried the test version.

Are you able to revert to 3.7.4 after testing?

[DownedAviator]

I tested it at KMSP, the same airport where MSFS crashed to desktop several times before.
Just to mention, I don’t think it’s a model issue. I’m using FSHud together with the AIG flight plans and models.

I did notice that FSHud injects around 20 aircraft less.
Maybe you can test what happens if you reduce AIGTC injection.

For info:

I did my recent MSFS 2020 testing of 3.7.4 at EGLL iniBuilds London Heathrow and VHHH WF Scenery Hong Kong International, always with AIGTC injection limited to 75%.

[capt_pero]

New very interesting finding:

1) Starting in EPWA Gate 15 at current time (1500z), load AIG - no CTD
2) Close AIG > Restart AIG > no CTD
3) Close AIG > Change time to 13.15z > Load AIG > CTD

Reproduceable. So it looks like the new GSX Version gets in conflict with an or multiple AIG model?!

Can someone pls try to reproduce this with MSFS2020?

[capt_pero]

I created SimConnect log files to determine whether a particular aircraft or model is the last one loaded, in order to find out if it is causing the CTD.
The strange thing is that the crash occurs at a specific point in EPWA and is reproducible.

And it happens on default EPWA as well.

Conclusion:
- not depending on a specific aircraft model
- not depending on a scenery

I have no idea how to keep on searching...

[AlexMas]

Hi
I have CTDs few days ago. I post my tests in other topic about same problems. I use GSX and Beyond ATC traffic, that uses AIG and FSLTL models.
Last Saturday I had my first CTD in EHAM between 14.00 and 16.00 zulu. My GSX autostarts then BeyondATC injects traffic and CTD. No problem in other airport (LGAV at that time). EHAM on Sundays NO CTDs. Today (Thursday at 19.00 in EHAM) first Beyond ATC injects traffic, then start manually GSX and CTD again.
I see in BEYONDATC support forum topics about this issue and they have a main suspect (GSX)

[renkouchuan]

Can someone confirm that the crash is reproduceable at different airports?
For me it looks like some are working without CTD and others (EPWA) causing a CTD when using GSX and AIG is injecting traffic.

I did test in all major Asian airports (RJAA RJTT ZSPD VHHH VTBS WSSS etc) with 100% AIG injections and CTD all over the place. I tried to reduce injection to 50% or even 20%, still CTD. Big airports with most AI is the best sample because before 3.7.4 I didn’t get any issues for that heavy load or heavier. I don’t think the issue is related to a certain model because I’ve talked to AIG and they didn’t change any model last several weeks. Now if we talk about simobjects amount, the only resolution is reducing AI injection, however, you can see my test result, reducing amount in big airports doesn’t help at all.

[renkouchuan]

Regarding to time, some local forums mentioned this issue significantly happened in Asia area so everyone doubted a time zone problem because when you load in an Asian airport you technically have a day ahead. I changed days backwards, daytime or night, early morning or dead midnight, no effect at all.

[jaawis]

Simply to fill in here a bit.

I've tried multiple injectors. FSHUD, BATC and AIGTC to be precise with MSFS2020 and still the same result, CTD. Tried both at small and large airports. I'm using AIG models. I did some tests with FSLTL models and that didn't always result in a CTD, not sure what that really means though, are they more lightweight somehow?

I'll try the beta and see how that works. 

[renkouchuan]

Simply to fill in here a bit.

I've tried multiple injectors. FSHUD, BATC and AIGTC to be precise with MSFS2020 and still the same result, CTD. Tried both at small and large airports. I'm using AIG models. I did some tests with FSLTL models and that didn't always result in a CTD, not sure what that really means though, are they more lightweight somehow?

I'll try the beta and see how that works. 

You are right. FSLTL injects way less AI than AIG TC because it only gets live flights plus some ground parked aircraft which is adjustable. AIGTC injects live flights and local offline weekly planned flights together to fill your airport. That’s why somebody saw less CTD on FSLTL. Anyway, like I said, before 3.7.4 my pc can handle an airport with almost 200 ramp spots full of AI with still a very reasonable FPS. The problem is not about that.

[Solox51]

Hi, I hope this can help in some way. I am still using MSFS 2020 and since the last update I am also having the issue with the CTDs. First I have tried to disable the couatl.exe from loading. Strangely I still had the CTDs as soon as I started a flight, airport and airplane didn´t matter. The only way to stop the CTDs was by deactivating the license which removed three linked GSX folders from the Community folder. Could the issue be lying in one of these three folders? By the way, I am using FSLTL and haven't changed anything in the settings for a very long time. Is it possible for us to just use the previous version until the culprit is found? I would really like to be able to use GSX!

[DownedAviator]

Now, for full disclosure, I'm running a slightly updated version of GSX, that contains some fixes for some likely (but maybe not) unrelated problems with .NET. They should be unrelated, since they would happened with 3.7.3 as well, but in case they are, I suggest trying the Beta updater I posted here and see if it makes any difference:

Please test with the original 3.7.4 version that we are reporting problems with and using MSFS 2020.

[virtuali]

Please test with the original 3.7.4 version that we are reporting problems with and using MSFS 2020.

Of course I won't do that: that will be part of the next update, and I don't see how it's helping anybody knowing if an soon to be outdated version could cause this, of course I couldn't replicate it with the older version, but I didn't test MSFS 2020. Now I also cannot replicate it with MSFS 2020 as well, but I'll always use the new version, and I urge everybody affected with this problem to test ONLY with the updated version I posted before, and I'll post it again now:

EDIT

The Fix is now included in the normal 3.7.5 update.

[AlexMas]

I did a test right now, with the updated GSX. Same result with BeyondATC injector: instant CTD. Maybe I did something wrong when installed the update version dowloaded from your link. I run the Addon Manager, install and play. I see that GSX needs manual start, despite in exe.html is set as autostart ( <Name>Couatl</Name>
    <Disabled>False</Disabled>)
 

[virtuali]

UPDATE: I managed to finally get my first CTD, using AIG models injected with BATC so, at least, I have something to work with now.

[virtuali]

UPDATE

After being able to replicate the CTD, the fix was in fact quite easy.

Along the entire GSX code, in all places where we read the airplane "Title" (AI or User), we always used a string with up 256 characters, even if the official Simconnect specs says the Title can be up to 128 characters max. However, in the new centralized AI manager code that has been added in 3.7.4 so it could be shared between the Map and the new Progressive Taxi function, for some reason, the string to do the Simconnect request was set to be 64 characters.

This caused Simconnect to crash internally, if there were any AIs with names longer than 64 characters and, sure enough, there are several models in AIG with titles of 70+ characters.

The interesting thing is: in MSFS 2024 this Simconnect bug has been FIXED! Even if I purposely limit the max string size to 64 characters and there are AIs with longer titles, the sim returns what you would expect: a title truncated to 64 characters, as you can see in this test I just made by adding logging titles for all AIs at EPWA injected with BATC:

AIGAIM_LOT Polish Airlines Embraer EMB-195 - Belly Titles
AIGAIM_LOT Polish Airlines Embraer EMB-175
AIGAIM_LOT Polish Airlines Boeing 737 MAX 8 - Wifi dome Belly Ti

The last one has a title longer than 64 characters, and in MSFS 2020 it would have caused Simconnect to crash internally when queried, but in MSFS 2024 it just returns the truncated title (as expected), without crashing. It even works if I make a request with 32 chars strings; all AI titles are returned truncated to 32 chars, with no crashes:

AIGAIM_Wizz Air Airbus A321-200S
AIGAIM_LOT Polish Airlines Embra
AIGAIM_LOT Polish Airlines Embra
AIGAIM_LOT Polish Airlines Embra

It's very likely somebody must have reported this to Asobo for MSFS 2024, since I was very surprised to find they fixed a bug in Simconnect that must have been there for years. Unfortunately, to fix it in MSFS 2020 would require an update of the sim, but it's not really an issue, since now that we found the underlying cause, the fix was really easy.

Setting the max string length to 256 like the rest of the GSX code has fixed the CTD with AIG for me. If you download again the Beta version, it's already updated with the fix:

EDIT

The Fix is now included in the normal 3.7.5 update.